Coil-retaining device.



Patented July 23, l90l.

J. T. H. DEMPSTER. COIL. RETAINING DEVICE.

(Application filed Mar. 26. 1901.)

,(No Model.)

\ INVENTOR. WITNESSES P JoHNT. LDEMPSTER,

I Z W, 1 B11 WW flTT'Y.

UNITED STATES JOHN T. H. DEMPSTER, OF SOHENEOTADY, NEW YORK, ASSIGNOR T O GENERAL ELECTRIC COMPANY, OF NEW YORK.

COIL-RETAINING DEVICE.

SPECIFICATION forming part of Letters Patent No. 678,864, dated July 23, 1901.

Application filed March 28, 1901. Serial No. 53,192. (No'modeh) To 01. whom it may concern.-

Be it known that 1, JOHN T. H. DEMPSTER, a subject of the King of Great Britain, residing at Schenectady, in the county of Schenec-' tady, State of New York, have invented certain new and useful Improvements in Coil- Retaining Devices, (Case No. 1,721,) of which the following is a specification.

' My present invention relates to means for retaining'coils in position in slots formed in the structure of dynamoelectric machines, and comprises more particularly certain improvements in the slotclosing or coil-retaining device used in this connection. Heretofore the common practice has been to make the coil-retaining device of wood of suitable cross-section, generally dovetailed. In accordance with my present invention the wooden strip employed for this purpose is reinforced by sheet metal, preferably iron or steel, clenched around the edges which engage the sides of the slot. This construction adds mechanical strength to the slot-closing device, and at the same time, by reason of the presence of the magnetic material, decreases the magnetic reluctance of the teeth between which the slot or slots exist.

In the drawings, Figure 1 is a perspective view of a slot-closing device built in accordance with my invention, while Fig. 2 represents the same applied to the armature of a dynamo-electric machine.

In Fig. 1 the slot-closing device will be seen to consist of a strip 1 of wood or other nonmagnetic material. Longitudinal grooves 2, 3, 4, and 5 are formed on the upper and lower surfaces of the strip, the purpose of these grooves being to form a retaining means for the reinforcing-strips 6 and 7 of sheet metal clenched about the opposite edges of the strip, as shown. The strip 6, for example, may first be rolled so as to fit over the edge of the wooden strip 1. The metal strip 6 being then placed in position on the wooden strip 1, the two are passed through a suitable rolling device, which turns in the edges of the metal strip 6, so as engage or clench with the grooves 2 3, formed in the wooden strip 1,as above mentioned. By a repetition of the operation the metal strip 7 is secured to the opposite edge of the wooden strip 1.

Fig. 2 represents the application to a dynamo'electric machine of the slot-closing de vice shown in detail in Fig. 1. The field-magnet of the machine is represented at 8 and the armature, which in this case is slotted, at 9. These slots contain armature-coils, as indicated, for example, at 10, the slots being closed and the coils retained in place by means of the slot-closing devices indicated at 11, these slot-closing devices, as before mentioned, being constructed as shown in Fig, 1.

It is obvious that various modifications of myinvention may be made without departing from the spirit thereof, for which reason I do not wish to be limited to the precise details of construction herein set forth. For a more precise statement of my invention reference is therefore to be had to the appended claims.

What I claim as new, and desire to secure by Letters Patent of the United States, is

1. The combination with a dynamo-electric machine having coil-retaining slots, of composite slot-closing devices of magnetic and non-magnetic material.

2. The combination with a dynamo-electric machine having coil-retaining slots, of selfretaining slot-closing devices composed partly of magnetic material and partly of non-mag- 8o netic material.

3. As an article of manufacture, a slot-closing device consisting of a reinforced strip of non-magnetic material.

4. As an article of manufacture, a slot- Wedge for dynamo-electric machines consisting of a strip of non-magnetic material reinforced with sheet metal.

5. As an article of manufacture, a slotwedge for dynamo-electric machines consist- 9o ing of a strip of non-magnetic material reinforced with sheet iron or steel.

6. A slot-closin g device consisting'of a strip of non-magnetic material having an edge or edges reinforced with sheet metal.

7. A slot-closing device consisting of a strip of non-magnetic material having an edge or edges reinforced with sheet-iron.

In witness whereof I have hereunto set my hand this 26th day of March, 1901.

' JOHN T. H. DEMPSTER.

Witnesses:

BENJAMIN B. HULL, FRED Russ. 

